The present invention relates to a semiconductor device, and particularly to technology that can be effectively adapted to a multi-pin semiconductor package in which a semiconductor chip consisting of a large-scale integration circuit having a high degree of integration is molded with a sealing material.
Heretofore semiconductor chips have been protected basically by being molded with a resin.
For instance, there is a technology in which use is made of a lead frame having a central portion thereof called a tab on which a semiconductor chip is to be mounted. Regarding such mounting technology, the semiconductor chip is first mounted on the tab and then the entire device is molded with a sealing material composed of the resin. According to this prior art technique, bonding pads arranged along the periphery on the main surface of the semiconductor chip are connected to the corresponding inner leads via, for example, bonding wires.
A problem common in the semiconductor packages of the prior art is that the sealing material is cracked at the portions where the leads of the metallic lead frame protrude beyond the sealing material, i.e., the sealing material is cracked along the parting line of the metal mold.
Another problem is that pollutants such as Na.sup.+ ions in the environment infiltrate into the semiconductor chip from the external side along the boundary between the leads and the resin when the semiconductor chip is constructed in a large size, and the passage of infiltration becomes relatively short as the size of the semiconductor chip becomes great. That is, pollutants infiltrate easily.
There further exists a problem in that relatively long bonding wires are necessary to connect the inner leads to the bonding pads of the semiconductor chip.
In order to solve the above-mentioned problems, there has been proposed a semiconductor device, such as semiconductor device of the LOC (lead-on-chip) structure, in which a plurality of inner leads are adhered onto the circuit-forming surface of a semiconductor chip using an adhesive agent via an insulating film, said inner leads are electrically connected to the semiconductor chip via bonding wires, and the device is molded with a resin, and in which a common inner lead (bus-bar inner lead) is provided near the center line on the circuit-forming surface of the semiconductor chip in the lengthwise direction (U.S. Pat. No. 4,862,245 assigned to International Business Machines Co.).